This invention relates to vascular procedures and more particularly to a docking assembly for the extension of a guidewire with an extension wire, comprising plug means and socket means, in which the plug means are releasably held in the socket means.
It is common practice to use a guidewire for the placement of a catheter in vascular procedures such as angioplasty. A guidewire typically is slightly longer than the catheter with which it is used, whereby a relatively short portion of the guidewire protrudes proximally form the catheter when the catheter is in place. If it becomes necessary to exchange the catheter, for instance to increase the balloon size in an angioplasty procedure, the guidewire must be removed and replaced by an exchange wire which is about twice the length of the catheter in order to allow withdrawal of the catheter and insertion of a new catheter over the exchange wire. However, this technology seriously complicates and slows down the vascular procedure, and there has been several attempts to attach an extension wire to the initial guidewire in order to eliminate the need of a separate exchange wire.
The document EP 0321796 A2 describes an extendable guidewire system comprising a main guidewire section and a guidewire extension section and a connection therebetween including a tubular member fixed to the end of one of the guidewire sections and a male member arranged on the end of the other guidewire section which has a maximum radial dimension which is greater than the inner diameter of the tubular member, whereby the male member may be inserted into the tubular member to releasably secure to two guidewire sections together.
According to a first embodiment, the male member is shaped into an undulating or sinusoidal shape. According to a second embodiment, the male member is provided with a smaller diameter portion having radial protrusions.
Hence, deformation of the undulating shape of the male member provides for a friction fit of the male member into the tubular member and the two guidewire sections may be connected or disconnected as desired. The need of radial deformation of the preshaped male member to generate the friction fit requires a distinct difference in diameter between the inner diameter of the tubular member and that of the male member. Therefore, the male member has to be extremely thin and it may be easily bent inadvertently, thereby spoiling the guidewire section to which it belongs. Furthermore, as the insertion of the male member into the tubular member is made against friction forces, these forces may cause buckling, and even total kinking of the male member with sinusoidal shape, also spoiling the corresponding guidewire section. In case of the male member with radial protrusions the male member is straight and will show less tendency to buckling and kinking upon insertion but the male member then is very difficult to manufacture. No special tool or pliers are used in this system to form the lock by the user, however the system relies entirely on friction forces. Upon contact with body fluids or medication fluids the friction surfaces may become slippery so that the required friction forces are no longer available.
U.S. Pat. No. 4,917,103 shows a guidewire system in which a steel tubular connector is attached to the proximal end of a guidewire and a reduced diameter steel tip is attached to the distal end of an extension wire.
The contrary is also possible, with the tubular connector on the extension wire and the reduced diameter tip on the guidewire. For connecting the extension wire to the guidewire, the reduced diameter tip is inserted into the tubular connector and the assembly of both the tip and connector is crimped by means of appropriate pliers used as a crimping tool. Mechanical attachment of both parts is thus obtained by displacing a segment of both the tubular connector and tip inserted therein laterally of their general axis in what may be considered as a generally U-shaped configuration. The extent of lateral displacement is of course selected so that it will not interfere too much with the smooth advancement of a catheter over the point of assembly. To release or disconnect the assembly of guidewire and extension wire, it is necessary to cut the guidewire distally of the crimp or to break the connection at the location of the crimped tubular connector and tip assembly.
The system is thus a permanent connection, and when released by cutting the guidewire or breaking the connector and tip assembly, both the guidewire and extension wire are spoiled, which makes it that the system is definitely not re-usable. In addition, the cutting-out of the guidewire or the breaking of the connector and tip assembly may prove difficult or even impossible without some special cutting tool. And this adds to the fact that the need to use a crimping tool for the mechanical attachment of the tubular connector and tip renders the system dependent from the proper use of the crimping tool. This system has the advantage that it has no preshaped male member that may be buckled or a male member with protrusions that are difficult to manufacture. It has also the advantage that it does not rely entirely on friction forces which makes this system more independent from potential wetting influences by body fluids or by medical fluids, however this system has the drawback that the extension can only be made with the help of some additional tool.
It is an object of this invention to improve the possibilities of attaching an extension wire to a guidewire and to avoid the aforesaid drawbacks. It is a further object of the invention to achieve attachment and release of a guidewire and extension wire by means of a docking assembly which is simple, inexpensive and easy to manufacture, which guarantees a smooth, effortless, efficient and repetitive operation for both connection and release of the guidewire and extension wire, which does not require skills or tooling manipulations, and which is still reliably locking even after being wetted with slippery fluids.